Display screen protective film with high blue light blocking properties and its manufacturing process

Abstract

This invention discloses a display screen protective film with high blue light blocking properties and its manufacturing process, belonging to the technical field of display screen protective films. The display screen protective film with high blue light blocking properties includes a buffer frame and a film body, which are integrally formed by hot pressing. The buffer frame is made of modified EPDM rubber and has a U-shaped groove for engaging with the display screen. The film body includes a substrate layer, a blue light blocking layer, and a functional coating connected in sequence. The display screen protective film with high blue light blocking properties and its manufacturing process provided by this invention not only combine organic blue light absorbing materials with inorganic blue light reflective layers in the blue light blocking layer design to achieve efficient blue light filtering, but also provide excellent impact absorption capabilities for the display screen through the buffer frame made of modified EPDM rubber.

Description

Technical Field

[0001] This invention relates to the field of display screen protective film technology, specifically to a display screen protective film with high blue light blocking properties and its manufacturing process. Background Technology

[0002] With the widespread use of electronic devices, screen usage time has increased significantly, and prolonged exposure to blue light can lead to eye fatigue, retinal damage, and even sleep disorders. Currently, most blue light protection films on the market use single-layer organic dye absorption or simple coating technology, which suffers from low blocking efficiency, insufficient mechanical strength, and a tendency to yellow. Furthermore, traditional protective films are mostly glued to the screen, making them non-removable, inflexible in use, and lacking cushioning structures, resulting in poor impact resistance. Summary of the Invention

[0003] The purpose of this invention is to provide a display screen protective film with high blue light blocking properties and its manufacturing process. By combining organic blue light absorbing materials with inorganic blue light reflective layers in the design of the blue light blocking layer, efficient blue light filtering is achieved, improving the durability and reliability of the product and solving the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a display screen protective film with high blue light blocking properties, comprising a buffer frame and a film body, wherein the buffer frame and the film body are integrally formed by hot pressing, the buffer frame is made of modified EPDM rubber material, and a U-shaped groove is provided on the buffer frame for engaging with the display screen, the film body is installed on the surface of the display screen through the buffer frame to protect the display screen, and the film body comprises a substrate layer, a blue light blocking layer and a functional coating connected in sequence.

[0005] Preferably, the modified EPDM rubber is prepared as follows: First, EPDM rubber is placed in a mixer at a temperature of 80-100℃ and a speed of 30-50 rpm, and short-cut carbon fibers are slowly added to prevent agglomeration. Paraffin oil and oxidant are added in sequence and mixed for 8-10 minutes until the carbon fibers are evenly dispersed. The temperature of the open mill is controlled at 60℃, and peroxide vulcanizing agent DCP and crosslinking agent TAIC are added. The mixture is passed through a thin sheet 3-4 times to ensure uniformity before sheeting.

[0006] Preferably, the modified EPDM rubber comprises the following raw materials in parts by weight:

[0007] The composition consists of 90-110 parts of ethylene propylene diene monomer (EPDM) rubber, 6-10 parts of chopped carbon fiber, 2-4 parts of dicumyl peroxide, 1-2 parts of TAIC, 4-7 parts of zinc oxide, and 12-18 parts of paraffin oil. The EPDM rubber has an ethylene content of not less than 60%, high molecular chain flexibility, and a resilience of over 85%.

[0008] Preferably, the method for preparing the buffer frame is as follows:

[0009] Preheat the mold to 160-180℃, inject the modified EPDM rubber at an injection pressure of 80-100Mpa, use a medium-low speed to prevent fiber sedimentation, hold the pressure for 30 seconds, cool for 60 seconds, remove the molded EPDM part from the mold, cool to room temperature, and wipe the surface with isopropanol to remove any residual mold release agent.

[0010] The EPDM components are laid flat on a high-temperature resistant tray and placed into a vacuum vulcanizing tank. The temperature is precisely controlled at 170°C and the time is 5 minutes. After vulcanization, the components are immediately removed and allowed to cool slowly at room temperature. This completes the vulcanization process.

[0011] The EPDM parts undergo surface pretreatment, first by plasma cleaning, then by spraying a silane primer onto the EPDM parts. After spraying, bake at 60℃ for 5 minutes. Dilute the fluorosilicone resin to a viscosity of 15-20 cP, and use a 0.3 mm nozzle spray gun with an air pressure of 0.3 MPa to spray a surface film onto the EPDM parts. The film thickness is 5-10 μm. Bake in an oven at 80℃ for 30 minutes to form a low-friction surface.

[0012] Preferably, the substrate layer is made of PET or TPU material, both of which have high transparency, good mechanical strength, and strong impact resistance.

[0013] Preferably, the blue light blocking layer is made of an organic blue light absorbing layer and an inorganic blue light reflecting layer, wherein the organic blue light absorbing layer is made of organic blue light absorbing material by solution coating, and the inorganic blue light reflecting layer is made of inorganic nanoparticles by magnetron sputtering deposition onto the surface of the organic blue light absorbing layer.

[0014] Preferably, the blue light blocking layer is prepared by the following method:

[0015] The organic blue light absorbing material is dissolved in a solvent, and acrylic resin is added as a film-forming agent. Microgravure coating is used with a screen count of 200-300 lines / inch and a coating speed of 20-30m / min. The material is dried with hot air at 80-100℃ for 1-2 minutes and then UV cured to enhance adhesion. After drying, the thickness of the organic blue light absorbing layer is 1-3μm.

[0016] Two inorganic nanoparticle materials are alternately deposited, each layer with a thickness of 100-120 nm, and the total number of layers is 5 or 7, forming an inorganic blue light reflective layer.

[0017] Preferably, the functional coating includes at least an anti-glare layer and an anti-fingerprint layer. The anti-glare layer contains silica microparticles to reduce surface reflection, and the anti-fingerprint layer is provided with a fluorosilane coating, which is hydrophobic and oleophobic.

[0018] Preferably, the film body further includes an optical matching layer, which is made of nano-ZrO2-doped acrylic resin to adjust the refractive index, reduce interface reflection, and improve light transmittance.

[0019] Another technical problem to be solved by the present invention is to provide a manufacturing process for a display screen protective film with high blue light blocking properties, comprising the following steps:

[0020] Step 1: Inject the modified EPDM rubber material into the mold for molding, and then perform post-vulcanization and surface treatment processes to form a buffer frame with a U-shaped groove.

[0021] Step 2: Perform plasma cleaning on the surface of the substrate layer for later use;

[0022] Organic blue light absorbing materials are dissolved in a solvent, coated by microgravure, and dried to form a uniform thin film. Inorganic nanoparticle materials are sputtered onto the thin film in a vacuum environment to form a blue light blocking layer.

[0023] A material for spin-coating an optical matching layer between a substrate layer and a blue light blocking layer, with a thickness of 50-100nm, is cured at 80℃ for 10 minutes to connect the substrate layer and the blue light blocking layer.

[0024] The blue light blocking layer is coated with an anti-glare coating and an anti-fingerprint coating, then laser-cut to match the screen size, and the edges are treated with explosion-proof material.

[0025] Step 3: Embed the edge of the membrane body into the U-shaped groove of the buffer frame, and heat press it with optical adhesive OCA at a temperature of 70℃, a pressure of 0.5MPa, and a time of 10 seconds.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] The blue light blocking display protective film and its manufacturing process provided by this invention not only combine organic blue light absorbing materials with inorganic blue light reflective layers in the blue light blocking layer design to achieve highly efficient blue light filtering, but also provide excellent impact absorption capabilities for the display screen through a buffer frame made of modified EPDM rubber. Furthermore, the anti-glare and anti-fingerprint layers in the functional coating further enhance the user experience, while the optical matching layer effectively reduces interface reflection and improves light transmittance. The overall structure is integrally molded by hot pressing, ensuring a tight bond between the layers and improving the product's durability and reliability. Attached Figure Description

[0028] Figure 1 This is an overall structural diagram of the display screen protective film with high blue light blocking properties of the present invention;

[0029] Figure 2 This is a cross-sectional view of the membrane body of the present invention.

[0030] In the figure: 1. Buffer frame; 11. U-shaped groove; 2. Membrane body; 21. Substrate layer; 22. Blue light blocking layer; 221. Organic blue light absorbing layer; 222. Inorganic blue light reflecting layer; 23. Functional coating; 231. Anti-glare layer; 232. Anti-fingerprint layer; 24. Optical matching layer. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1:

[0033] Please see Figures 1-2 Take 100 parts by weight of EPDM rubber, 8 parts of carbon fiber, 3 parts of DCP, 1.5 parts of TAIC, 5 parts of zinc oxide, and 15 parts of paraffin oil.

[0034] First, put EPDM rubber into a mixer at 80℃ and 50rpm, and slowly add short-cut carbon fibers to prevent agglomeration. Then, add paraffin oil and oxidant in sequence, mix for 8 minutes until the carbon fibers are evenly dispersed. Control the temperature of the open mill at 60℃, add DCP and TAIC, and pass through the mill 3-4 times to ensure uniformity before sheeting.

[0035] Preheat the mold to 160-180℃, inject the modified EPDM rubber at an injection pressure of 100Mpa, use a medium-low speed to prevent fiber sedimentation, hold the pressure for 30 seconds, cool for 60 seconds, remove the molded EPDM part from the mold, cool to room temperature, and wipe the surface with isopropanol to remove any residual mold release agent.

[0036] The EPDM components are laid flat on a high-temperature resistant tray and placed into a vacuum vulcanizing tank. The temperature is precisely controlled at 170°C and the time is 5 minutes. After vulcanization, the components are immediately removed and allowed to cool slowly at room temperature. This completes the vulcanization process.

[0037] The EPDM parts are pretreated by plasma cleaning, followed by spraying with silane primer. After spraying, they are baked at 60°C for 5 minutes. Fluorosilicone resin is diluted to a viscosity of 15-20 cP and sprayed onto the EPDM parts with a surface film of 5-10 μm thickness using a 0.3 mm nozzle and an air pressure of 0.3 MPa. The parts are then baked at 80°C for 30 minutes to form a low-friction surface, thus creating the buffer frame 1.

[0038] 0.2mm PET was selected as the substrate layer 21 with a light transmittance of 93%. The organic blue light absorbing layer 221 was made of 8wt% benzotriazole. The benzotriazole was dissolved in acetone, and acrylic resin was added as a film-forming agent. Microgravure coating was used at a coating speed of 30m / min. It was dried with hot air at 80℃ for 1-2 minutes and then UV cured to enhance adhesion. After drying, the film thickness of the organic blue light absorbing layer 221 was 1-3μm.

[0039] The inorganic blue light reflective layer 222 consists of 7 layers of TiO2 / SiO2 with a total thickness of 840nm. Two kinds of inorganic nanoparticle materials are alternately deposited on the organic blue light absorbing layer 221, with each layer having a thickness of 100-120nm, for a total of 7 layers, thus forming the inorganic blue light reflective layer 222.

[0040] An acrylic resin doped with nano-ZrO2 was spin-coated between the substrate layer 21 and the blue light blocking layer 22. The thickness was 60 nm, and the resin was cured at 80°C for 10 minutes to connect the substrate layer 21 and the blue light blocking layer 22.

[0041] SiO2 particles are mixed with acrylic resin and sprayed onto the surface of blue light blocking layer 22 with a haze of 15% to form anti-glare layer 231. UV curing is then used, and a fluorosilicone resin coating is sprayed onto the surface of anti-glare layer 231 to form anti-fingerprint layer 232.

[0042] The edge of the film body 2 is embedded in the U-shaped groove 11 of the buffer frame 1, and then hot-pressed with optical adhesive OCA at a temperature of 70°C, a pressure of 0.5MPa, and a time of 10 seconds to produce a display screen protective film with high blue light blocking properties.

[0043] Example 2:

[0044] 110 parts by weight of EPDM rubber, 65% ethylene content, 10 parts carbon fiber, 3 parts DCP, 1.5 parts TAIC, 5 parts zinc oxide, and 15 parts paraffin oil were prepared. The EPDM rubber was modified using the same method as in Example 1 to prepare the buffer frame 1. The substrate layer 21 was made of 0.3mm TPU. The inorganic blue light reflective layer 222 of the blue light blocking layer 22 was 5 layers of CeO2 / SiO2, each layer was 110nm, and contained 0.1wt% graphene. Other materials were the same as in Example 1. The display screen protective film with high blue light blocking was processed using the method of the example.

[0045] Example 3:

[0046] 95 parts by weight of EPDM rubber, 10 parts by weight of carbon fiber, 3 parts by weight of DCP, 1.5 parts by weight of TAIC, 5 parts by weight of zinc oxide, and 15 parts by weight of paraffin oil were used to modify EPDM rubber using the same method as in Example 1. Buffer frame 1 was prepared. The substrate layer 21 was made of 0.15mm PET. The organic blue light absorbing layer 221 of the blue light blocking layer 22 was made of 10wt% benzotriazole. The inorganic blue light reflective layer 222 was made of 7 layers of Nb2O5 / SiO2. Antibacterial silver ions were added to the anti-glare layer 231, and the haze was 10%. Other materials were the same as in Example 1. The display screen protective film with high blue light blocking properties was processed using the method of the example.

[0047] Comparative Example 1:

[0048] In this comparative example, the blue light blocking layer 22 is a 3μm organic blue light absorbing layer 221. The inorganic blue light reflecting layer 222 is omitted in this comparative example, and the other structures are the same as in Example 1.

[0049] Comparative Example 2:

[0050] In this comparative example, the buffer frame 1 structure is omitted, and ordinary OCA adhesive is directly bonded to the membrane body 2. Other structures are the same as in Example 1.

[0051] The display protective films with high blue light blocking properties prepared in the above embodiments and comparative examples were subjected to performance tests, and the following data were obtained:

[0052]

[0053]

[0054] The embodiments utilize an organic absorption + inorganic reflection multilayer structure, achieving a blue light blocking rate of >89%, significantly superior to the single-layer organic film of Comparative Example 1. Comparative Example 2 lacks a buffer frame, resulting in poor mechanical properties. The modified EPDM buffer frame + TPU / PET substrate combination of the embodiments exhibits excellent performance in the drop ball impact test, while Comparative Example 2 is prone to cracking. In Embodiment 3, due to the addition of fluorosilicone resin and an antibacterial layer, ΔYI is only 0.8, demonstrating the best wear resistance.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A display screen protective film with high blue light blocking properties, comprising a buffer frame (1) and a film body (2), characterized in that: The buffer frame (1) and the membrane body (2) are integrally formed by hot pressing. The buffer frame (1) is made of modified EPDM rubber material. A U-shaped groove (11) is provided on the buffer frame (1). The U-shaped groove (11) is used to engage with the display screen. The membrane body (2) includes a substrate layer (21), a blue light blocking layer (22), and a functional coating (23) connected in sequence. The blue light blocking layer (22) is made of an organic blue light absorbing layer (221) and an inorganic blue light reflecting layer (222). The organic blue light absorbing layer (221) is made of organic blue light absorbing material by solution coating, and the inorganic blue light reflecting layer (222) is made of inorganic nanoparticles by magnetron sputtering coating onto the surface of the organic blue light absorbing layer (221). The preparation method of the blue light blocking layer (22) is as follows: The organic blue light absorbing material is dissolved in a solvent, and acrylic resin is added as a film-forming agent. Microgravure coating is used with a screen count of 200-300 lines / inch and a coating speed of 20-30m / min. The material is dried with hot air at 80-100℃ for 1-2 minutes and then UV cured to enhance adhesion. After drying, the thickness of the organic blue light absorbing layer (221) is 1-3μm. Two inorganic nanoparticle materials are alternately deposited, each layer with a thickness of 100-120 nm, and the total number of layers is 5 or 7, forming an inorganic blue light reflective layer (222). The two inorganic nanoparticle materials are titanium dioxide (TiO2) and silicon dioxide (SiO2), or niobium pentoxide (Nb2O5) and silicon dioxide (SiO2). The membrane body (2) also includes an optical matching layer (24), which is made of nano-ZrO2-doped acrylic resin and is disposed between the substrate layer (21) and the blue light blocking layer (22).

2. The display screen protective film with high blue light blocking properties according to claim 1, characterized in that: The modified EPDM rubber is prepared as follows: First, EPDM rubber is placed in a mixer at a temperature of 80-100℃ and a speed of 30-50 rpm, and short-cut carbon fibers are slowly added to prevent agglomeration. Paraffin oil and oxidant are added in sequence and mixed for 8-10 minutes until the carbon fibers are evenly dispersed. The temperature of the open mill is controlled at 60℃, and peroxide vulcanizing agent DCP and crosslinking agent TAIC are added. The mixture is passed through the mill 3-4 times to ensure uniformity before sheeting.

3. The display screen protective film with high blue light blocking properties according to claim 2, characterized in that: The modified EPDM rubber comprises the following raw materials in parts by weight: The composition consists of 90-110 parts of ethylene propylene diene monomer (EPDM) rubber, 6-10 parts of chopped carbon fiber, 2-4 parts of dicumyl peroxide, 1-2 parts of TAIC, 4-7 parts of zinc oxide, and 12-18 parts of paraffin oil, wherein the ethylene content of the EPDM rubber is not less than 60%.

4. The display screen protective film with high blue light blocking properties according to claim 1, characterized in that: The preparation method of the buffer frame (1) is as follows: Preheat the mold to 160-180℃, inject the modified EPDM rubber at an injection pressure of 80-100Mpa, hold the pressure for 30 seconds, cool for 60 seconds, remove the molded EPDM part from the mold, cool to room temperature, and wipe the surface with isopropanol to remove any residual mold release agent. The EPDM components are laid flat on a high-temperature resistant tray and placed into a vacuum vulcanizing tank. The temperature is precisely controlled at 170°C and the time is 5 minutes. After vulcanization, the components are immediately removed and allowed to cool slowly at room temperature. This completes the vulcanization process. The EPDM parts undergo surface pretreatment, first by plasma cleaning, then by spraying a silane primer onto the EPDM parts. After spraying, bake at 60℃ for 5 minutes. Dilute the fluorosilicone resin to a viscosity of 15-20 cP, and use a 0.3 mm nozzle spray gun with an air pressure of 0.3 MPa to spray a surface film onto the EPDM parts. The film thickness is 5-10 μm. Bake in an oven at 80℃ for 30 minutes to form a low-friction surface.

5. The display screen protective film with high blue light blocking properties according to claim 1, characterized in that: The substrate layer (21) is made of PET or TPU material.

6. The display screen protective film with high blue light blocking properties according to claim 1, characterized in that: The functional coating (23) includes at least an anti-glare layer (231) and an anti-fingerprint layer (232). Silica microparticles are added to the anti-glare layer (231), and the anti-fingerprint layer (232) is provided with a fluorosilane coating, which is hydrophobic and oleophobic.

7. A manufacturing process for a display screen protective film with high blue light blocking properties as described in claim 6, characterized in that, Includes the following steps: Step 1: The modified EPDM rubber material is injected into the mold and molded, and then subjected to post-vulcanization and surface treatment processes to form a buffer frame (1) with a U-shaped groove (11); Step 2: Perform plasma cleaning on the surface of the substrate layer (21) for later use; Organic blue light absorbing material is dissolved in a solvent, coated by a microgravure plate, and dried to form a uniform film. Inorganic nanoparticle material is sputtered onto the film in a vacuum environment to form a blue light blocking layer (22). The material of the optical matching layer (24) with a thickness of 50-100nm is spin-coated between the substrate layer (21) and the blue light blocking layer (22), and cured at 80°C for 10 minutes to connect the substrate layer (21) and the blue light blocking layer (22). Spray anti-glare layer (231) coating and anti-fingerprint layer (232) coating on the surface of blue light blocking layer (22), laser cut, match the screen size, and make explosion-proof treatment on the edges; Step 3: Embed the edge of the membrane body (2) into the U-shaped groove (11) of the buffer frame (1), and use optical adhesive OCA for hot pressing and bonding at a temperature of 70℃, a pressure of 0.5MPa, and a time of 10 seconds.

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